Electromagnetic pump for internal-combustion engines



March 4, 194.7. J. B. PARSONS 6, 3

ELECTROMAGNETIC PUMP FOR INTERNAL COIBUSTIONBNGINES Original Filed llarch s, 1943 Patented Mar. 4, 1947 ELECTROMAGNETIC PUMP FOR INTERNAL- COMBUSTION ENGINES John B. Parsons, Toledo, Ohio, assignor to Malcolm W. Fraser, trustee, Toledo, Ohio Original application March 3, 1943, Serial No. 477,841. Divided and this application November 10, 1943, Serial No. 509,676

5 Claims.

This invention relates to fuel pumps particularly adapted for internal combustion engines, and an object is to produce a new and improved fuel pump which is adapted to deliver fuel under pressure to the carburetor and to return excess fuel from the carburetor to the supply tank or reservoir.

Another object is to provide a fuel pump of the above character which is electromagnetically operated, and has the new and improved features of construction, arrangement and operation hereinafter desscribed,

Other objects and advantages will hereinafter appear and for purposes of illustration but not of limitation, an embodiment of the invention is shown on the accompanying drawings in which Figure 1 is a side elevation partly in section of a. fuel system for an internal combustion engine particularly adapted for vehicles showing the electromagnetic pump and carburetor with connecting duct lines, the carburetor being shown diagrammatically; ..:I

Figure 2 is an enlarged vertical sectional elevation of the electromagnetic pump;

Figure 3 is a sectional view substantially on the line 33 of Figure 2; and

Figure 4 is a transverse section on the line 44 of Figure 1.

This application constitutes a division of my" copending application Serial No. 477,841, filed March 3, 1943, entitled Fuel system for internal combustion engines.

The illustrated embodiment of the invention comprises a fuel system for internal combustion engines, more particularly engines for motor ve-" hicles, and as shown, A represents an electromagnetic pump which is designed to pump liquid fuel from a tank T, through a tube l and force the fuel to a carburetor B through a tube H. The pump A also operates to withdraw excess fuel from the carburetor B through the tube l Thus while the engine is operating, a continuous flow of gasoline is maintained through the carburetor and this is important for keepin the carburetor relatively cool and militating against fuel loss caused by heat from the carburetor. Ample fuel is retained in what might be termed a constant level chamber so that even though the vehicle is on an extremely sharp upward incline, suflicient pressure head will be maintained at all times in the region of the jet. Furthermore, the carburetor is so designed that when the engine is idle, the fuel drains from the constant level chamber.

Referring more particularly to the drawings, the electromagnetic pump A comprises 'a block l4 and a block I 5 between which is clamped a flexible diaphragm IS, a series of cap screws l1 securin the blocks together and retaining the diaphragm IS in position. As will hereinafter appear, the block I5 is formed with ports, passages and provided with valves for-controlling the flow of liquid fuel from the tank T to the carburetor B and the block I4 is provided with ports, passages and valves controlling the flow of fuel from the carburetor to the tank.

A pump chamber l1 enables reciprocatory flexing operation of the diaphragm Hi to effect the desired pumping operation and clamped on opposite sides of the diaphragm are discs l8 and I9 which fit over a reduced end of a vertically reciprocatory plunger 2|. Suitable means is provided ,.for securely retaining the discs l8 and IS on the reduced end portion 20 so that as the l' dh ger 2| reciprocates, the diaphragm will effeet the desired pumping action Within the chamber ll. The upper portion of the plunger 2| has a sliding fit Within a, cylinder 22 which is integral with and projects upwardly from the upper portion of the block l4. Intermediate the upper portion of the plunger 2| and the lower reduced end portion 20 is an intermediate reduced portion 23 of somewhat less diameter than the inner diameter of the cylinder 22. The plunger 2| is formed with an axially extending socket or bore 24 which is open at its upper end and terminates in the intermediate portion 23 at its lower end. Directly beneath the bore 24 is a slightly smaller bore 25 and directly beneath the bore 25 is a still smaller bore or socket 26.

Seated at the lower end of the bore 24 is a washer 21 against which abuts the lower end of a coil spring 28., The upper end of the coil spring 28 bears against the under side of a plug 29 which fits in and closes the upper end of the cylinder 22. The plug 29 is retained in place by pins 30 and a suitable sealing ring 3| carried by the plug provides an effective seal between the plug and the cylinder. It will be manifest that the plunger 2| is slidable within the cylinder 22 and causes reciprocatory flexing movement of the diaphragm l6.

Slidable centrally through the plug 29 is a switch operating pin 32 which passes through the coil spring 24 and the washer 21. At the lower end of the pin 32 is a head 33 which is adapted to abut against the under side of the washer 21 in the downward movement of the plunger, and

' to abut against the shoulder forming the lower wardly. The upper operating pin 32 manner by a resilient disc 34 preferably of synthetic rubber.

:disc 34. is recessed as ;34 fits in liquid tight portion 31 H the disc in a path defined by the embossed porj tion 31 and the recess movement of the switch has a neck 38 which receives 1 of an upwardly bowed spring contact 5 The spring plate 40 is integral with the cross 1 plate 4| which has a contact point engageable 3 a pair of insulating of and are insulated from I plate 52 providing i contact plate or strip the influence of the coil spring will be engaged by the washer 21 slightly before end of the bore 25 when the plunger moves upend portion of the switch is snugly engaged in leak proof vAs shown, the upper end of the the central portion of the indicated at 36. The disc contact within a socket provided in the plug 29 and is clamped in place by a plate 35 which has an upwardly embossed to afford limited flexing movement of plug in the region of 36 during the reciprocatory operating pin 32.

of the operating pin 32 the notched end 39 plate 40.

The upper end portion with a contact point on a strip 42 mounted on posts 43. The cross plate 4| is integral with a pair or side plate members 44 which are integral with an end plate portion 45. The plate portion 45 fits in a suitable groove in an adjusting nut 45 which is threaded on a post 41. A nut 48 on the post 41 clamps the plate 35 in position.

and 52 are disposed at opposite ends the solenoid coil, the a mounting for the post 41. The insulating posts 43 are carried by the plate 35 and the latter is secured by screws 48a as well as the nut 48.

One terminal of the solenoid 49 or 53 as indi cated on Figure 3, is electrically connected to the 42. Also electrically connected'to the opposite end of the plate 42 is a small resistance coil 54 which has its opposite end attached to an ear 55 struck up from the plate 52. The resistance coil 54 militates against arcing at the contact points when the latter are opened. The opposite terminal of the solenoid coil 49 extends to a source of electrical energy such as through the usual ignition switch 49a on the automobile so that when the ignition switch is turned to the on position, the solenoid 49 will be energized.

From the above description, it will be manifest that the switch is of the simple over-center spring type, the arched or bowed spring 40 being such thatwhen the switch operating pin 32 reaches a Plates 5| predetermined position in downward movement, be closed and when in a prethe contacts will determined upper or raised position, the contacts will be open. It will further be understood that the reduced bore 25 in which the head 33 of the operating pin is disposed, is of sufflcient depth that as the plunger 2| .moves downwardly under 28, the head 33 the diaphragm l6 has completed its downward pumping movement, whereupon the contacts will be closed to cause the solenoid 49 to be energized thereby to cause the plunger 2| to move upwardly. Such upward movement continues until the shoulder at the .bottom end of the reduced bore 25 engages the head 33 of the operating pin, again to operate the switchto de-energize the solenoid 49. When the electric current is turned oil, the diaphragm will assume the position shown in Figure 2 under the influence of the coil spring 28. A metallic cup-shaped housing 55 fits over the switch and solenoid parts and cooperates with the plates 5| and 52 to provide a path for the magnetic flux, and may be held in place in any suitable manner.

The switch adjusting nut 48 should be turned so that the contact points are in open position slightly before the plunger 2=| comes into contact with the plug 29 and in closed position slightly before the plunger reaches its lower limit of travel.

From the above description, it will be manifest that so long as the ignition switch 49a is on, the diaphragm I6 will be flexed recurrently to effect a pumping action within the chamber I1 f is forced past the valve 59 and 1 tially leak proof and arranged within the block |5 are valves 51 and 58 and within the block l4 are valves 59 and 68. The valves 51 and 60 are intake valves and the valves 58 and 59 are outlet valves. The arrangement is such that when the diaphragm I6 is flexed upwardly, liquid is drawn into the chamber H on the under side of the inlet port 6| through the valve 51 and liquid which is on the upper side of the diaphragm l6 from the block |4 through the outlet port 62. On the other hand, when the diaphragm 6 moves downwardly the liquid trapped on the under side of the diaphragm I6 is forced from the chamber |1 past the valve 58 and from the block l5 through the outlet port 63. At the same time liquid is drawn into the chamber |1 above the diaphragm |6 through the inlet port 64 and past the valve 60. Except for the different arrangement of the valves, they are of similar construction, each hav- 7 ing a seating portion 65 which is backed up by a coil spring 56, the seating surface being substanand of material resistant to gasoline, such, for example, as synthetic rubber.

Manifestly the valves are seated and unseated due to the difference in pressures. Although it is desirable that the several valve springs 66 be reasonably light, it is desirable that the valve spring for the valve 58 be somewhat stronger in order to hold that valve seated against the liquid pressure created when the fuel tankof the vehicle is elevated above the carburetor.

It will be observed that the fuel entering the block |5 through the port 6| does not pass directly to the valve 51. On the contrary, the fuel passes through a substantially L-shaped passage 61 to a sediment bowl 68, thence through a screen or filter 69 and through a passage 10 to the valve 51. A cap screw 1| holds the bowl 68 and filter screen 69 in place, the latter seating in the bowl as indicated.

The fuel from the pump A passing through the tube or duct enters the carburetor B through a passage 12 which leads to a constant level chamber 13 having upstanding walls 14 forming with the wall 15 a four-sided chamber. The

gasoline or other fuel is adapted to flow over the fuel is forced into the constant level chamber 18 and thence may overflow the walls 14 into the overflow chamber 16 from which it is pumped through the tube |2. Through the wall 15 inclines upwardly a jet nozzle 11 which leads to the Venturi passage 18 in the air horn and can thence pass downwardly past the butterfly valve 19 to the engine cylinders, the top 8|] being open in the usual manner.- .A small vent 9| leads from the chamber 13 to the air horn as indicated.

One important feature of the invention resides in the provision of a drain opening 82 in one of the walls 14 affording a communication between the diaphragm from the lower end portion of the chamber 13 and the overflow chamber 16, such drain opening being disposed below the entrance to the jet nozzle 11. This drain opening 82 is of paramount importance because it militates against so-called percolation of the gasoline when the engine is hot and not operating since it is efiective in draining substantially all of the gasoline from the cham'- ber 13 and thus from the region of the jet nozzle or nozzles 11. As a consequence, the constant level chamber 13 is free of gasoline at all times except when the engine and fuel pump A are in operation. It should be understood that the drain hole or tube 82 is relatively small and although fuel is constantly leaking through it, the amount is of no consequence during engine operation. The lower end of the overflow chamber 16 is somewhat deeper than the constant level chamber 13 so that liquid may flow readily through the drain tube 82.

If desired, the walls 14 of the constant level chamber 13 may incline inwardly toward the air horn or carburetor throat so that when the vehicle is climbing a grade, the fuel level may remain nearly constant or it may incline-sharply upward thereby to cause the fuel level to be raised under these conditions. In any case, however, the level of the fuel in the chamber 13 is lowered relatively to the jet nozzle 11 when the vehicle is descending a grade. As shown in Figure 4, the constant level chamber 13 at least partially surrounds the carburetor throat so that when the carburetor is tilted to the right as viewed in Figure 1, liquid fuel is maintained at nearly a constant level with respect to the jet nozzle 11. i

In some cases it may be desirable to control the operation of the pump A by means of a thermostatic switch which would be responsive to carburetor temperature so that even when the engine is idle, the pump would be in operation should the carburetor temperature exceed a predetermined maximum.

It is to be understood that numerous changes in details of construction, arrangement and operation may be effected without departing from the spirit of the invention especially as defined in the appended claims.

What I claim is:

l. A fuel pump of the type having a pumping chamber of constant displacement, a diaphragm one side of the chamber, a plunger secured at one end to a central portion of the diaphragm and sliding in said cylinder, solenoid motormeans for actuating the movement of said plunger in one direction, and spring means for actuating the movement of said plunger in the opposite direction, a pin mounted coaxially and enclosed by said plunger and slidable therein with one end portion extending therethrough, a

- pin abutment surfaces for rendering said solenoid motor mean operable upon movement in said one direction and inoperable upon movement in the opposite direction.

3. In a fuel pump of the type having a casing defining a pumping chamber, a diaphragm operable in said chamber, a pair of spring tensioned inlet and outlet valves on opposite sides of the diaphragm, a cylinder rigid with said casing and projecting outwardly from one side of the pumping chamber, a plug fitting the outer end of the cylinder, a sealingring fitting a recess in said plug and abutting the cylinder surface thus serving as a barrier to the passage of fluids or vapors, a plunger reciprocable within said cylinder and fixed at its inner end to said diaphragm, solenoid motor means for actuating the movement of said plunger in one direction, and spring means for actuating the movement of said plunger in the opposite direction, said spring means being disposed within said cylinder with one end abutting against said plug, the other end seating upon a shoulder within said plunger, a pin disposed coaxially within said plunger and slidable through said plug beyond which said pin extends, a flange associated with the enclosed portion of said pin, spaced abutments operable in said chamber, means for actuating said diaphragm in one direction and spring means for actuating said diaphragm in the opposite direction, said pump comprisin a pair of inlet and outlet valves on opposite sides of the diaphragm whereby upon actuation of said pump in one direction fluid is drawn through the inlet valve on one side of the diaphragm, while fluid on the other side of the diaphragm is discharged through the outlet valve, said valves being spring tensioned and the outlet valve on the feed side having a slightly stronger spring to counteract the additional force of the fluid head.

2. In a fuel pump of the type having a casing defining a pumping chamber, a diaphragm operable in said chamber, a pair of inlet and outlet valves on opposite sides of the diaphragm whereby upon actuation thereof in one direction fluid is drawn through the inlet valve on one side and fluid is discharged through the outlet valve on the other side, flat rigid discs disposed on opposite sides of the diaphragm, a cylinder rigid with said casing and projecting outwardly from associated with said plunger engageable with the flanged portion of said pin for recurrently actuating the same in one direction or the other in response to plunger movement, spaced abutments on the free end portion of said pin, and means associated with said pin abutment sur- -faces for rendering said solenoid motor means operable upon movement in said one direction and inoperable upon movement in the opposite direction.

4. In a fuel pump of the type having a casing defining a pumping chamber, a flexible diaphragm operable in said chamber, a pair of "spring tensioned inlet and outlet valves on opposite sides of the diaphragm, the spring for the outlet feed valve being slightly stronger than the springs of the remaining valves to compensate for the added force of the fluid head, a cylinder rigid with said casing and projecting outwardly from one side of the pumping chamber, a fluid tight plug fitting the outer end portion of the cylinder, a plunger reciprocatory within the cylinder and fixed at its inner end to the diaphragm, a disc seating upon a shoulder within said plunger, solenoid motor means for actuating the movement of said plunger in one direction and spring means for actuating the movement of said plunger in the opposite direction, said spring means being disposed within said cylinder with one end abutting against said plug and the other end seating upon said disc, a pin slidable through said plug and arranged with a portion extending within said cylinder, a resilient disc snugly engaging the pin at the central portion, means for anchoring the edge portions of said disc thereby to provide a liquid seal for said pin, a flange integral with the enclosed end portion of said pin, spaced abutments associated with said plunger engaging the flanged portion of said pin for recurrently actuating the same in one direction or the other in response to plunger movement, spaced abutments on the free end portion of said pin, and means in cooperation therewith for rendering said solenoid motor means operable upon pin movement in said one direction and inoperative upon movement in the opposite direction.

5. A fuel pump as claimed in claim 4, in which the spaced abutments associated with said plunger arecomprised of the disc seating upon the shoulder within-the plunger and against which the spring bears, and another shoulder formed by a bore of smaller diameter continuing downwardly within the plunger, the distance between abutments being spaced for contact with the end portion of the pin during the 5 fina1 movements of the plunger in the upwardly or downwardly direction.

JOHN B. PARSONS.

10 REFERENCES CITED The following references are of record in the file of this patent: Y

UNITED STATES PATENT 15 Number Name Date 2,179,925 Dilg Nov. 14, 1939 1,883,459 Avigdor Oct. 18, 1932 1,380,442 Trumble June 7, 1921 v 2,139,346 Babitch et a1 Dec. 6, 1938 20 2,111,970 Gillan Mar. 22, 1938 

